Method of depositing a silicon dioxide comprising layer doped with at least one of P, B and Ge

ABSTRACT

A substrate is positioned within a deposition chamber. At least two gaseous precursors are fed to the chamber which collectively comprise silicon, an oxidizer comprising oxygen and dopant which become part of the deposited doped silicon dioxide. The feeding is over at least two different time periods and under conditions effective to deposit a doped silicon dioxide layer on the substrate. The time periods and conditions are characterized by some period of time when one of said gaseous precursors comprising said dopant is flowed to the chamber in the substantial absence of flowing any of said oxidizer precursor. In one implementation, the time periods and conditions are effective to at least initially deposit a greater quantity of doped silicon dioxide within at least some gaps on the substrate as compared to any doped silicon dioxide deposited atop substrate structure which define said gaps.

TECHNICAL FIELD

[0001] This invention relates to methods of methods of depositingsilicon dioxide comprising layers doped with at least one of P, B andGe.

BACKGROUND OF THE INVENTION

[0002] Silicon dioxide is a regularly used insulating material insemiconductor processing in the fabrication of integrated circuitry. Oneparticular class of silicon dioxides are those doped with at least oneof phosphorus, boron and germanium. Examples include phosphosilicateglass (PSG), borosilicate glass (BSG) and borophosphosilicate glass(BPSG). Such materials might be utilized as fill material in trenchisolation, as interlevel dielectrics, and as well as in many otherapplications. A typical manner of depositing such materials is bychemical vapor deposition (CVD), which includes atomic layer deposition.In one exemplary CVD process, silicon, dopant and oxidizing precursorsare continuously fed to a deposition reactor under conditions effectiveto in situ deposit a doped silicon dioxide layer on a substrate receivedtherein. Alternately by way of example only, a substantially undopedsilicon dioxide layer can be formed first, followed by ion implanting ordiffusion doping of the desired dopants therein.

[0003] A usual or typical goal in silicon dioxide layer depositions isto attain a conformal covering over the substrate. A substantiallyconformal deposition is characterized by a substantially constantdeposition thickness over all of a substrate, including over the highelevation areas, the low elevation areas, and the interconnectingsurfaces therebetween. However in many such processes, a non-conformaldeposition occurs whereby more material tends to deposit on the higherelevation substrate features than on the lower or lowest elevation ofgaps between features. This can lead to “bread loafing” and the ultimateocclusion of the gaps resulting in undesirable void formation within thegaps. Such can be overcome with doped silicon dioxides as describedabove by a high temperature anneal/reflow step whereby the doped silicondioxide is substantially liquified, thereby flowing to fill the gaps.However, such is not always effective, adds additional processing steps,and may not be practical as device geometries continue to be decreasedhorizontally without a corresponding decrease in the vertical geometriesof the circuitry.

[0004] While the invention was motivated in addressing the above issuesand improving upon the above-described drawbacks, it is in no way solimited. The invention is only limited by the accompanying claims asliterally worded (Without interpretative or other limiting reference tothe above background art description, remaining portions of thespecification or the drawings) and in accordance with the doctrine ofequivalents.

SUMMARY

[0005] The invention includes methods of depositing silicon dioxidecomprising layers doped with at least one of P, B and Ge. In oneimplementation, a substrate is positioned within a deposition chamber.At least two gaseous precursors are fed to the chamber whichcollectively comprise silicon, an oxidizer comprising oxygen and dopantwhich become part of the deposited doped silicon dioxide. The feeding isover at least two different time periods and under conditions effectiveto deposit a doped silicon dioxide layer on the substrate. The timeperiods and conditions are characterized by some period of time when oneof said gaseous precursors comprising said dopant is flowed to thechamber in the substantial absence of flowing any of said oxidizerprecursor. In one implementation, the time periods and conditions areeffective to at least initially deposit a greater quantity of dopedsilicon dioxide within at least some gaps on the substrate as comparedto any doped silicon dioxide deposited atop substrate structure whichdefine said gaps.

[0006] Other aspects and implementations are contemplated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

[0008]FIG. 1 is a diagrammatic depiction of a deposition chamber usablein accordance with an aspect of the invention.

[0009]FIG. 2 is a diagrammatic section view of a substrate fragmentprocessed in accordance with an aspect of the invention.

[0010]FIG. 3 is a diagrammatic section view of another substratefragment processed in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] This disclosure of the invention is submitted in furtherance ofthe constitutional purposes of the U.S. Patent Laws “to promote theprogress of science and useful arts” (Article 1, Section 8).

[0012] An exemplary method of depositing a silicon dioxide comprisinglayer doped with at least one of P, B and Ge is described, by way ofexample only, with reference to FIG. 1 Such depicts any suitabledeposition chamber 10 having a substrate 12 positioned therein.Preferably, substrate 12 comprises a semiconductor substrate upon whichintegrated circuitry has been or is being fabricated. In the context ofthis document, the term “semiconductor substrate” or “semiconductivesubstrate” is defined to mean any construction comprising semiconductivematerial, including, but not limited to, bulk semiconductive materialssuch as a semiconductive wafer (either alone or in assemblies comprisingother materials thereon), and semiconductive material layers (eitheralone or in assemblies comprising other materials). The term “substrate”refers to any supporting structure, including, but not limited to, thesemiconductive substrates described above.

[0013] Chamber 10 is diagrammatically depicted as having four gas inletstreams A, B, C, and D. Of course, more or fewer streams/flows couldalso be utilized, and also with any of such being combined upstream ofdeposition chamber 10. In one preferred embodiment, such wouldultimately feed to a showerhead (not shown) which would be receivedabove substrate 12. An exemplary vacuum controlling drawdown/exhaustline 14 extends from chamber 10 for exhausting unreacted gas andby-product from the substrate, and for controlling chamber pressure.

[0014] In accordance with one aspect of the invention, the substrate tobe deposited upon is positioned within a deposition chamber, for examplesubstrate 12 within an exemplary deposition chamber 10. At least twogaseous precursors are fed to the chamber with such precursorscollectively comprising silicon, an oxidizer comprising oxygen, anddopant which become part of the doped silicon dioxide layer beingdeposited. The feeding is over at least two different time periods andunder conditions effective to deposit a doped silicon dioxide layer onthe substrate. The time periods and conditions are characterized by someperiod of time when one of the gaseous precursors comprising the dopantis flowed to the chamber in the substantial absence of flowing any ofthe oxidizer precursor. In one preferred embodiment, the “some” periodof time is repeated multiple times during the deposition.

[0015] In the context of this document, “in the substantial absence”means no greater than 1% of the subject precluded precursor flowing tothe reactor in the subject period of time as compared to the sum of allother precursors flowed to the reactor, excluding inert gaseousmaterial. The “no greater than 1%” refers to or is calculated as avolumetric ratio of the flow rates of the subject precursors in sccm,not factoring in any carrier gas flow. In certain preferredimplementations, the “substantial absence” is further limited to mean nodetectible level or levels of the subject/precluded precursor beingflowed to the chamber during the subject time period.

[0016] In one preferred aspect, such time periods and conditions areeffective to at least initially deposit a greater quantity of dopedsilicon dioxide within at least some gaps on the substrate as comparedto any doped silicon dioxide deposited atop substrate structures whichdefine such gaps. An exemplary reduction-to-practice example isdescribed below.

[0017] The ultimate dopant could comprise any one or a combination of P,B and Ge. By way of example only, an exemplary precursor for phosphorusdopant is TEPO (triethylorthophosphate) of the formula P(OC₂H₅)₃. Anexemplary precursor for boron is TEB (triethylborate) of the formulaB(C₂H₅)₃. An exemplary precursor for germanium is germane (GeH₄).

[0018] The substrate temperature and/or chamber pressure might besubstantially constant during the subject feedings, or not besubstantially constant. In the context of this document and with respectto temperature, “substantially constant” means maintaining within 5% in° C., and with respect to pressure means within 5% in Torr. Further, anyof such feedings might include plasma generation or be in the absence ofplasma. Where plasma generation is conducted, such could occur in one orboth of within the chamber and remote from the chamber.

[0019] In one preferred implementation, the time period when one of thegaseous precursors comprising the dopant is flowed to the chamber in thesubstantial absence of flowing any of the oxidizer precursor also occursin the substantial absence of flowing any of the precursor comprisingthe silicon which gets deposited onto the substrate.

[0020] The respective of at least some of the different time periodsmight overlap or none of the time periods overlap. In one preferredembodiment, there is some period of time intermediate two differentperiods of time that do not overlap which is characterized by asubstantial absence of any precursor flow to the chamber, and in onemore preferred embodiment characterized by an inert gas flow to thechamber intermediate such two different periods.

[0021] Exemplary preferred precursors constituting an oxidizer whichcomprises oxygen which predominately ends up in the incorporated silicondioxide layer include ozone and activated oxygen, for example by plasmageneration. By way of example only, an alternate example includes N₂Oand other NO_(x) materials.

[0022] In one implementation, a method of depositing PSG comprisespositioning a substrate within a deposition chamber. At least TEOS, TEPOand another oxygen containing gas are fed to the chamber as reactionprecursors over a plurality of time periods and under conditionseffective to deposit a PSG comprising layer on the substrate. The timeperiods and conditions are characterized by a first period of time whenat least one of the TEOS and TEPO flows to the chamber in thesubstantial absence of the other oxygen containing gas to the chamber.Further, the time periods and conditions are characterized by a secondperiod of time following the first when the other oxygen containing gasflows to the chamber in the substantial absence of flowing any of theTEOS and TEPO to the chamber. The first period of time might becharacterized by flowing both the TEOS and TEPO to the chamber at thesame time. Alternately by way of example only, the first period of timemight be characterized by flowing only one of the TEOS and TEPO to thechamber in the substantial absence of flowing the other. Further in suchlatter example, the time periods and conditions might be characterizedby a third period of time following the second when the other of theTEOS and TEPO flows to the chamber in the substantial absence, offlowing the TEOS or TEPO which was flowed to the chamber during thefirst period of time and also in the substantial absence of flowing theother oxygen containing gas to the chamber. Attributes as describedabove could also be utilized in this implementation, as well as otherattributes.

[0023] In one implementation, a method of depositing a silicon dioxidecomprising layer doped with at least one or P, B and Ge includespositioning a substrate within a deposition chamber. At least an “a”precursor, a “b” precursor and a “c” precursor are fed to the chamber.The “a” precursor comprises silicon which becomes part of the depositeddoped silicon dioxide. The “b” precursor comprises an oxidizercomprising oxygen which becomes part of the deposited doped silicondioxide. The “c” precursor comprises dopant which becomes part of thedeposited doped silicon dioxide. As above, an exemplary “a” precursor isa silane, such as monosilane. An exemplary “b” precursor is ozone,activated oxygen and/or N₂O. Exemplary “c” precursors would, of course,depend on the desired doped silicon dioxide layer being deposited and,by way of example only, could include any one or combination of TEPO,TEB and germane.

[0024] The feeding of such “a”, “b” and “c” precursors is over at leastthree different respective time periods and under conditions effectiveto deposit a doped silicon dioxide layer on the substrate. The timeperiods and conditions are characterized by some period of time when the“c” precursor is flowed to the chamber in the substantial absence offlowing any of the “b” precursor, and more preferably also in thesubstantial absence of flowing any of the “a” precursor. In oneexemplary embodiment, there is another period of time characterized byflowing both the “c” precursor and the “a” precursor to the chamber atthe same time.

[0025] Again and as with the above-described embodiment, some of thestated time periods might overlap, or none of the stated time periodsoverlap. Further where two time periods do not overlap, there may besome period of time intermediate two of the time periods which ischaracterized by a substantial absence of any precursor flow to thechamber, and further by way of example only, characterized by an inertgas flow to the chamber in the substantial absence of any precursor flowto the chamber.

[0026] The above-described feeding involving “a”, “b” and “c” precursorscan be considered in a collection as constituting some cycle. In onepreferred embodiment, the subject feedings occur over a plurality ofrepeating such cycles of “a” precursor, “b” precursor and “c” precursorflowings to the chamber. Of course, a respective/individual cycle mightinclude only one, or more than one, of any one of the “a”, “b” and “c”precursor flowings. In one preferred embodiment, individual of repeatingcycles are characterized by two “b” precursor flows for every “a” plus“c” precursor flows.

[0027] Some of the above-described attributes in a combination aredescribed with respect to Table 1 below regarding but one exemplaryreduction-to-practice example. However, such example is not intended tobe limiting to the breadth of the disclosure, unless literally solimited in a particular claim under analysis. The invention iscontemplated and defined in the accompanying claims as literally worded,without limiting or interpretative reference to the specification.

[0028] A preferred substrate temperature during the depositions andprocessings of Table 1 are from 200° C. to 600° C., with such processingoccurring with a substantially constant substrate temperature of 350°C., and in a cold wall reactor not under plasma conditions. A preferredpressure range during the depositions and processings is from 1 Torr to200 Torr, with the pressure varying between 2 Torr and 6 Torr. A spacingfrom the showerhead to the substrate surface was constant during theprocessings at 230 mills. An exemplary preferred ozone flow is from 100sccm to 10,000 sccm, with 800 sccm being utilized in the below example.Such preferred ozone flow rates include O₂ flow, with the above suchflow rates preferably comprising from 1% to 20% by volume O₃. In theexample below, the ozone concentration was 12.5% by volume. TEOS andTEPO were provided to the reactor by flowing an inert gas at the rate of12 sccm through respective vaporizers to transfer the subject vapor tothe chamber. Preferred TEOS flow rates for a six liter volume reactorare from 50 mg/minute to 1000 mg/minute, with 600 mg/minute beingtransferred by the flowing helium in the example below. A preferred TEPOflow rate range is from 50 mg/minute to 500 mg/minute, with 200mg/minute being transferred by the flowing helium in the example below.TABLE 1 Time Period 1 2 3 4 5 6 7 8 O₃ off off on off off off on offTEOS on off off off off off off off TEPO off off off off on off off offPulse Time 3 10 10 10 3 10 10 10 (secs)

[0029] Table 1 depicts a first period of time over 3 secondscharacterized by TEOS flow and no ozone or TEPO flow. This was followedby a second period of time characterized by the substantial absence offlowing any of the ozone, TEOS and TEPO to the chamber. Alternately andperhaps more preferred would be some continuous flowing of an inert gasto the chamber, for example helium, argon and/or nitrogen, during anytime period depicted with all “off” flows.

[0030] The second time period was followed by a third time period inwhich ozone was flowed to the chamber while no TEOS or TEPO was flowedto the chamber. The third period of time was then followed by a fourthperiod of time in which no gas was flowed to the chamber. This was thenfollowed by a fifth period of time in which TEPO flowed to the chamberin the substantial absence of any ozone or TEOS flows. A sixth period oftime followed the fifth, and in which no precursor gases were flowed tothe chamber. This was followed by a seventh period of time in whichozone flowed to the chamber in the substantial absence of any TEOS orTEPO flowing to the chamber. An eighth period of time followed theseventh, and in which none of the ozone, TEOS or TEPO precursors flowedto the chamber. The above cycle is then repeated.

[0031] The deposition rate for the Table 1 indicated cycle was a 3 to 5Angstroms thick layer of doped silicon dioxide in the form of PSG. Sucha process initially formed a greater quantity of the doped silicondioxide within the gaps on the substrate as compared to any dopedsilicon dioxide which deposited atop the substrate structure whichdefined such gaps.

[0032] By way of example only, such a process might be used toultimately deposit a doped silicon dioxide layer having a thickness ofanywhere from 3 Angstroms to 1,500 Angstroms. At some point, it isexpected that the deposition would become substantially conformal,particularly after the gaps have been substantially filled.

[0033] By way of example only, FIGS. 2 and 3 depict substrate structureswherein the invention might be utilized. FIG. 2 depicts a substrate 20comprising a base substrate 22 having a pair of gate constructions 24and 26 formed thereover. By way of example only, such are shown as beingcharacterized by an insulating cap received over a conductive refractorymetal silicide layer, received over a conductively doped polysiliconlayer, received over a gate dielectric layer (not designated withnumerals). Anisotropically etched sidewall spacers are receivedthereabout. An exemplary doped silicon dioxide layer 28 has beendeposited, for example in accordance with the above-described Table 1 orother embodiments, wherein layer 28 at least initially deposits agreater quantity of the doped silicon dioxide within the gaps betweengate construction 28 as compared to atop structures 24 and 26 whichdefine such gap.

[0034]FIG. 3 depicts similar exemplary processing with respect toshallow trench isolation (STI), and by way of example only. FIG. 3depicts a bulk semiconductor substrate 30 having a pad oxide layer 32and a silicon nitride masking layer 34 formed thereover. Shallowtrenches 36 and 38 have been etched into the respective materials, asshown. By way of example and as described above, a doped silicon dioxidelayer 40 has been deposited to provide, at least initially, a greaterquantity of doped silicon dioxide within the trench gaps on thesubstrate as compared to any doped silicon dioxide which might bedeposited atop the adjacent substrate structure that defines such gaps.

[0035] Of course, with respect to the Table 1 reduction-to-practiceexample, any additional processing steps might be added, or some of theprocessing steps deleted or modified. By way of example only and in noway of limitation, the TEOS and TEPO flows could be reversed and/or onlya single ozone flow provided in the indicated cycle.

[0036] The mechanism by which such deposition occurs is not entirelyunderstood, but the following may be what is happening. This disclosureis in no way intended to be limited by any perceived theory ofoperation, whether correct or incorrect, unless so limited in aparticular claim under analysis. The deposition mechanism might includesome aspects of ALD or ALD-like processing, as well as by vapor or otherphase reaction. The particular deposition method may have ALD-likeaspects in that one or more of the precursors may be chemisorbing to thesubstrate as such substrate exists when the respective precursor isflowed to the chamber. However unlike ALD, the above-describedprocessing in the reduction-to-practice example was not self-limitingrelative to the different precursor flows. Accordingly, it is perceivedthat some of the flowing precursor might by physi-sorbing and/orchemisorbing to internal reactor surfaces as well as to the substratedesired to be deposited upon, and thereby are available for reactionwhen a subsequent precursor is flowed to the chamber. Further, suchphysisorbed and/or chemisorbed material may be providing a vapor phasereaction and immediate subsequent deposition onto the substrate withoutthe formation of monolayers typical in ALD. Further, it is possible thata combination of the above and ALD-like processing is occurring duringdeposition.

[0037] In compliance with the statute, the invention has been describedin language more or less specific as to structural and methodicalfeatures. It is to be understood, however, that the invention is notlimited to the specific features shown and described, since the meansherein disclosed comprise preferred forms of putting the invention intoeffect. The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A method of depositing a silicon dioxide comprising layer doped with at least one of P, B, and Ge, comprising: positioning a substrate within a deposition chamber; and feeding at least two gaseous precursors to the chamber collectively comprising silicon, an oxidizer comprising oxygen and dopant which become part of the deposited doped silicon dioxide, said feeding being over at least two different time periods and under conditions effective to deposit a doped silicon dioxide layer on the substrate, the time periods and conditions being characterized by some period of time when one of said gaseous precursors comprising said dopant is flowed to the chamber in the substantial absence of flowing any of said oxidizer precursor, the time periods and conditions being effective to at least initially deposit a greater quantity of doped silicon dioxide within at least some gaps on the substrate as compared to any doped silicon dioxide deposited atop substrate structure which define said gaps.
 2. The method of claim 1 wherein said some period of time is characterized by flowing said gaseous precursor comprising said dopant to the chamber in the substantial absence of flowing any of said precursor comprising said silicon.
 3. The method of claim 1 wherein none of the different time periods overlap.
 4. The method of claim 1 wherein at least some of the different time periods overlap.
 5. The method of claim 1 wherein at least some of the different time periods do not overlap.
 6. The method of claim 5 comprising some period of time intermediate two different time periods that do not overlap which is characterized by a substantial absence of any precursor flow to the chamber.
 7. The method of claim 5 comprising some period of time intermediate two different time periods that do not overlap in which an inert gas flows to the chamber in the substantial absence of any precursor flow to the chamber.
 8. The method of claim 1 wherein the dopant comprises phosphorus.
 9. The method of claim 8 wherein the deposited doped silicon dioxide at least predominately comprises PSG.
 10. The method of claim 1 wherein the dopant comprises B.
 11. The method of claim 1 wherein the dopant comprises Ge.
 12. The method of claim 1 wherein substrate temperature is substantially constant during the feeding.
 13. The method of claim 1 wherein chamber pressure is substantially constant during the feeding.
 14. The method of claim 1 wherein substrate temperature and chamber pressure are substantially constant during the feeding.
 15. The method of claim 1 wherein the substantial absence is below a detectable level of said oxidizer precursor.
 16. The method of claim 1 wherein said feeding comprises repeating said some period of time multiple times.
 17. The method of claim 1 wherein said feeding is in the absence of plasma.
 18. The method of claim 1 wherein said feeding comprises plasma generation.
 19. The method of claim 18 wherein the plasma generation is within the chamber.
 20. The method of claim 18 wherein the plasma generation is remote from the chamber.
 21. A method of depositing a silicon dioxide comprising layer doped with at least one of P, B, and Ge, comprising: positioning a substrate within a deposition chamber; and feeding at least an “a” precursor, a “b” precursor and a “c” precursor to the chamber, the “a” precursor comprising silicon which becomes part of the deposited doped silicon dioxide, the “b” precursor being an oxidizer comprising oxygen which becomes part of the deposited doped silicon dioxide, and the “c” precursor comprising dopant which becomes part of the deposited doped silicon dioxide, said feeding being over at least three different respective time periods and under conditions effective to deposit a doped silicon dioxide layer on the substrate, the time periods and conditions being characterized by some period of time when said “c” precursor is flowed to the chamber in the substantial absence of flowing any of said “b” precursor.
 22. The method of claim 21 wherein the time periods and conditions are effective to at least initially deposit a greater quantity of doped silicon dioxide within at least some gaps on the substrate as compared to any doped silicon dioxide deposited atop substrate structure which define said gaps.
 23. The method of claim 21 wherein at least two of the three time periods overlap.
 24. The method of claim 21 wherein none of the three time periods overlap.
 25. The method of claim 24 comprising some period of time intermediate two of the three time periods which is characterized by a substantial absence of any precursor flow to the chamber.
 26. The method of claim 24 comprising some period of time intermediate two of the three time periods that do not overlap in which an inert gas flows to the chamber in the substantial absence of any precursor flow to the chamber.
 27. The method of claim 21 wherein the “c” precursor comprises P.
 28. The method of claim 27 wherein the deposited doped silicon dioxide layer comprises PSG.
 29. The method of claim 21 wherein the “c” precursor comprises B.
 30. The method of claim 21 wherein the “c” precursor comprises Ge.
 31. The method of claim 21 wherein the feeding occurs over a plurality of repeating cycles of “a” precursor, “b” precursor and “c” precursor flowings to the chamber.
 32. The method of claim 31 wherein individual cycles are characterized by two “b” precursor flows for every “a” plus “c” precursor flows.
 33. The method of claim 21 wherein said some period of time is characterized by flowing said “c” precursor to the chamber in the substantial absence of flowing any of said “a” precursor.
 34. The method of claim 21 wherein there is another some period of time characterized by flowing both said “c” precursor and said “a” precursor to the chamber at the same time.
 35. A method of depositing PSG comprising: positioning a substrate within a deposition chamber; and feeding at least TEOS, TEPO and another oxygen containing gas as reaction precursors to the chamber, said feeding being over a plurality of time periods and under conditions effective to deposit a PSG comprising layer on the substrate; the time periods and conditions being characterized by a first period of time when at least one of said TEOS and TEPO flows to the chamber in the substantial absence of flowing said another oxygen containing gas to the chamber; and the time periods and conditions being characterized by a second period of time following the first when said another oxygen containing gas flows to the chamber in the substantial absence of flowing any of said TEOS and TEPO to the chamber.
 36. The method of claim 35 wherein the time periods and conditions are effective to at least initially deposit a greater quantity of doped silicon dioxide within at least some gaps on the substrate as compared to any doped silicon dioxide deposited atop substrate structure which define said gaps.
 37. The method of claim 35 wherein the first period of time is characterized by only one of said TEOS and TEPO flowing to the chamber in the substantial absence of flowing said other of said TEOS and TEPO to the chamber; the time periods and conditions being characterized by a third period of time following the second when said other of said TEOS and TEPO flows to the chamber in the substantial absence of flowing said TEOS or TEPO flowed during the first time period and in the substantial absence of flowing said another oxygen containing gas to the chamber.
 38. The method of claim 35 wherein the first and second time periods do not overlap.
 39. The method of claim 38 comprising some period of time intermediate the first and second periods of time which is characterized by a substantial absence of any precursor flow to the chamber.
 40. The method of claim 38 comprising some period of time intermediate the first and second periods of time in which an inert gas flows to the chamber in the substantial absence of any precursor flow to the chamber.
 41. The method of claim 35 wherein the feeding occurs over a plurality of repeating cycles of the first and second time periods with their associated precursor flows.
 42. The method of claim 41 wherein individual cycles are characterized by two another oxygen containing gas flows for every TEPO plus TEOS flows.
 43. The method of claim 35 wherein said first period of time is characterized by flowing both said TEPO and TEOS to the chamber at the same time.
 44. A method of depositing a silicon dioxide comprising layer doped with at least one of P, B, and Ge, comprising: positioning a substrate within a deposition chamber; feeding at least an “a” precursor, a “b” precursor and a “c” precursor to the chamber, the “a” precursor comprising silicon which becomes part of the deposited doped silicon dioxide, the “b” precursor comprising oxygen which becomes part of the deposited doped silicon dioxide, and the “c” precursor comprising dopant which becomes part of the deposited doped silicon dioxide, said feeding being over a plurality of time periods and under conditions effective to deposit a doped silicon dioxide layer on the substrate; the time periods and conditions being characterized by a first period of time when either said “a” or said “c” precursor flows to the chamber in the substantial absence of flowing the other of said “a” and “c” precursor to the chamber and in the substantial absence of flowing said “b” precursor to the chamber; the time periods and conditions being characterized by a second period of time following the first when there is a substantial absence of flowing any of said “a”, “b” and “c” precursors to the chamber; the time periods and conditions being characterized by a third period of time following the second when said “b” precursor flows to the chamber in the substantial absence of flowing any of said “a” and “c” precursors to the chamber; the time periods and conditions being characterized by a fourth period of time following the third when there is a substantial absence of flowing any of said “a”, “b” and “c” precursors to the chamber; the time periods and conditions being characterized by a fifth period of time following the fourth when said other of said “a” and “c” precursors flows to the chamber in the substantial absence of flowing said “a” or “c” precursor flowed during the first time period and in the substantial absence of flowing said “b” precursor to the chamber; the time periods and conditions being characterized by a sixth period of time following the fifth when there is a substantial absence of flowing any of said “a”, “b” and “c” precursors to the chamber; the time periods and conditions being characterized by a seventh period of time following the sixth when said “b” precursor flows to the chamber in the substantial absence of flowing any of said “a” and “c” precursors to the chamber; and the time periods and conditions being characterized by an eighth period of time following the seventh when there is a substantial absence of flowing any of said “a”, “b” and “c” precursors to the chamber.
 45. The method of claim 44 wherein “a” comprises TEOS and “c” comprises TEPO
 46. The method of claim 44 wherein “a” comprises TEOS and “c” comprises TEB.
 47. The method of claim 44 wherein “a” comprises TEOS and “c” comprises GeH₄.
 48. The method of claim 44 wherein the time periods and conditions are effective to at least initially deposit a greater quantity of doped silicon dioxide within at least some gaps on the substrate as compared to any doped silicon dioxide deposited atop substrate structure which define said gaps.
 49. The method of claim 44 wherein said first through eighth periods of time comprise a cycle, and further comprising repeating the cycle.
 50. The method of claim 44 wherein said first through eighth periods of time comprise a cycle, and further comprising repeating the cycle multiple times.
 51. The method of claim 44 wherein substrate temperature is substantially constant during the first through the eighth periods of time.
 52. The method of claim 44 wherein chamber pressure is substantially constant during the first through the eighth periods of time.
 53. The method of claim 44 wherein substrate temperature and chamber pressure are substantially constant during the first through the eighth periods of time.
 54. The method of claim 44 wherein the substantial absences are below respective detectable levels.
 55. The method of claim 44 wherein said feeding comprises plasma generation.
 56. The method of claim 55 wherein the plasma generation is within the chamber.
 57. The method of claim 55 wherein the plasma generation is remote from the chamber. 